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Kevin Doyle

Laurentian Bladder Fern (Cystopteris laurentiana)

Life history

Species overview

Laurentian Bladder Fern (Cystopteris laurentiana), a Wisconsin Special Concern plant, is found in moist, mostly wooded slopes and ledges in circumneutral soil. The optimal identification period for this species is late June through early September.

Synonyms: Cystopteris fragilis var. huteri, Cystopteris fragilis var. laurentiana, Cystopteris X laurentiana


  • Distinguishing characteristics: Distinguished from C. bulbifera by fronds broadest above (not at) the base, apex of fronds short (not long) attenuate, glandular hairs sparse (not dense) and bulblets uncommon (not frequent).
  • Flower characteristics:
  • Fruit characteristics: Sori dorsal on the laminae veins, protected by a pocket-like or scale-like, whitish, thin, commonly ciliate indusium; indusia cup-shaped, truncate at the apex.
  • Leaf characteristics: Narrowly elliptic-lanceolate, 9 to 21 cm long, 3.5 to 8 cm wide, widest near the middle, obtuse at the base, acute to acuminate at the apex, twice pinnate-pinnatifid at and above the base, pinnate-pinnatifid below the pinnatifid apex, veins in laminae terminating in teeth and emarginations of teeth, basal pinna pair often spaced rather distantly from the suprabasal pair.


  • Blooming phenology:
  • Fruiting phenology: early summer
  • Optimum time to identify: The optimal identification period for this species is late June through early September


  • Growth form: Fern
  • Vegetative reproduction: Rhizomatous
  • Life cycle: Perennial
  • Comments: Associated Species: Prenanthes alba, Aguilegia canadensis, Aster macrophyllus, Diervilla lonicera, Antennaria species, Cystopteris species, Sullivantia renifolia.

State status

Status and Natural Heritage Inventory documented occurrences in Wisconsin

The table below provides information about the protected status - state and federal - and the rank (S and G Ranks) for Laurentian Bladder Fern (Cystopteris laurentiana). See the Working List Key for more information about abbreviations. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Documented locations of Cystopteris laurentiana in the Natural Heritage Inventory Database as of July 2015.

Summary Information
State StatusSC
Federal Status in Wisconsinnone
State RankS2
Global RankG3
Tracked by NHIY

Habitats and landscapes

The Natural Heritage Inventory has developed scores indicating the degree to which each of Wisconsin's rare plant species is associated with a particular natural community or ecological landscape. This information is similar to that found in the Wildlife Action Plan for animals. As this is a work in progress, we welcome your suggestions and feedback.

General habitat information

  • Habitat description: Found in moist, mostly wooded slopes and ledges in circumneutral soil.
  • Soils: Limestone, dolomite, conglomerate, shale, and diabase cliffs and rocks.

Natural communities

This table lists the natural communities that are associated with Laurentian Bladder Fern. Scores for natural community associations are: "significant" association (score=3), "moderate association" (score=2) or the species can be present but is only weakly associated with the community (score=1).

Ecological landscapes

This table lists the ecological landscape association scores for Laurentian Bladder Fern. The scores (3=High, 2=Moderate, 1=Low, 0=None) also correspond to the map.

Map of the Ecological Landscapes of Wisconsin.

Species guidance

The Endangered Resources Program has developed avoidance measures and management guidelines for plants on the Natural Heritage Working List. These are a work in progress, and we welcome your suggestions and feedback. Sources used in developing this information can be found here.

Avoidance measures

These are specific actions designed to avoid "take" (mortality) of this species.

  • Avoid disturbance to moist limestone cliffs within forests where this species has been reported.
  • Avoid known individual plant locations and conduct operations elsewhere when they are least likely to cause damage. Ideally, this would involve frozen, snow-covered ground. However, in areas of the state where frozen conditions are unreliable, very dry soils late in the growing season might be the best available alternative. Consult with a biologist, if needed.
  • Avoid direct disturbance to sensitive microsites such as seeps, cliffs, and moss-covered boulders.
  • Avoid broadcast spraying of herbicides; use care with spot spraying.

Management guidance

Management guidelines are additional considerations that may help maintain or enhance habitat for this species

  • Maintain high forest canopy cover; this species requires shaded habitat conditions.
  • Buffer management around unique microhabitats such as ephemeral ponds, seeps, etc.
  • Follow BMPs, especially around streams and use care near ravines, steep slopes, cliffs, rock outcrops, etc.


Laurentian Bladder Fern Photo.

Photo by Kevin Doyle, Wisconsin DNR.

Laurentian Bladder Fern Photo.

Laurentian bladder fern (Cystopteris laurentiana) typically grows in small clusters from moist rock crevices.

Photo by Ryan O'Connor, Wisconsin DNR.

Laurentian Bladder Fern Photo.

Cystopteris laurentiana is an elongated fern and is slighter wider just above the base, which helps distinguish it from the more common C bulbifera, which is widest at the base.

Photo by Ryan O'Connor, Wisconsin DNR.

Laurentian Bladder Fern Photo.

Photo by Ryan O'Connor, Wisconsin DNR.

Laurentian Bladder Fern Photo.

Rounded bulblets (i.e., the two greenish-white structures along the rachis in the center of the photo) can occassionally be found on the underside of the leaves of Laurentian bladder fern.

Photo by Ryan O'Connor, Wisconsin DNR.

Support for Wisconsin's rare plant information has been provided by the Division of Forestry, the Endangered Resources Fund and the Wisconsin Rare Plant Preservation Fund. To donate, visit the Natural Resources Foundation of Wisconsin [exit DNR].

Last revised: Wednesday, May 05, 2021
Southwest Savanna Southern Lake Michigan Coastal Western Coulees and Ridges Southeast Glacial Plains Central Sand Hills Central Lake Michigan Coastal Central Sand Plains Northern Lake Michigan Coastal Northern Lake Michigan Coastal Northeast Sands Western Prairie North Central Forest Northern Highlands Northwest Lowlands Northwest Sands Northwest Lowlands Superior Coastal Plains Forest Transition